The present invention relates to a dome switch including a surface sheet having a dome-shaped protuberance, a spacer sheet, the circuit member, and an adhesive sheet.
FIG. 15 is an exploded perspective view of a poly-dome switch (dome switch) in a related art, FIG. 16 is a cross-sectional view of essential portions before the switching operation, and FIG. 17 is a cross-sectional view of the essential portions at the time of the switching operation.
In FIG. 15, a related poly-dome switch (dome switch) 1 used in a household electric appliance includes a surface sheet 2, a spacer sheet 3, a flexible printed circuit (FPC) 4, and an adhesive sheet 5, and is fixed to a plate 6 serving as an attaching member to be attached to with the adhesive sheet 5 interposed.
A plurality of dome-shaped protuberances 7 which project toward the outer surface side and are capable of being reversed toward the inner surface side are formed in the aforementioned surface sheet 2. Electrodes 8 (see FIG. 16) for the FPC 4 are respectively provided on the inner surfaces of the protuberances 7.
The spacer sheet 3 is a thin sheet member and is provided to prevent the deformation of the surface sheet 2. The spacer sheet 3 is provided with adhesive layers on its obverse and reverse surfaces, so that the surface sheet 2 and the FPC 4 can be fixed thereto. A plurality of through holes 9 are formed in the spacer sheet 3 in such a manner as to correspond to the positions of the protuberances 7. Further, slit-like air release portions 10 are respectively formed on both sides of the through holes 9.
The FPC 4 is a circuit member having a plurality of circuits routed in desired patterns. A plurality of contacts 11 which are contacted by the electrodes 8 (see FIG. 16) are provided on its spacer sheet 3 side. The FPC 4 is bonded and fixed to the adhesive sheet 5. The adhesive sheet 5 has the function as a reinforcing member.
In the above-described construction, the poly-dome switch 1 operates such that, as shown in FIG. 17, when the protuberance 7 is pressed down to effect a switching operation, the protuberance 7 is reversed toward the FPC 4 (the feeling of a click occurs at this time), and the electrode 8 is brought into contact with the contact 11 to energize the circuit. It should be noted that when the protuberance 7 is reversed toward the FPC 4, the air located on the inner surface side of the protuberance 7 is vented to the air release portions 10 through the through hole 9.
In the above-described poly-dome switch 1, the structure provided is such that the spacer sheet 3 and the FPC 4 are brought into surface contact with each other. For this reason, there has been a problem in that when an attempt is made to mount chip components on the FPC 4 and assemble them, the spacer sheet 3 is lifted off the FPC 4 and becomes deformed due to the effect of the height of the chip components. Incidentally, if the spacer sheet 3 is lifted off and becomes deformed, the switching function is naturally affected.
The invention has been devised in view of the above-described circumstances, and its object is to provide a chip-component accommodating structure in a dome switch which makes it possible to mount a chip component on a circuit member.
In order to solve the aforesaid object, the invention is characterized by having the following arrangement.
(1) A dome switch comprising:
a front sheet;
a dome-shaped protuberance which is formed on the front sheet so as to protrude outside, can be reversed inside and includes an electrode provided therein;
a circuit member having a contact point with which the electrode are brought into contact when the protuberance is reversed;
a spacer sheet which is interposed between the front sheet and the circuit member, and includes a through hole formed therein for ensuring contact between the electrode and the contact point;
an adhesive sheet including on one side a circuit attaching surface for the circuit member and on the other side a bonding and fixing surface for an attaching member; and
a spacer sheet-side accommodating portion, for accommodating a chip component mounted on a side of the circuit member where the contact is disposed, formed in the spacer sheet.
(2) The dome switch according to (1), wherein an embossed portion for the chip component is formed in the surface sheet in correspondence with a position of the spacer sheet-side accommodating portion.
(3) A dome switch comprising:
a front sheet;
a dome-shaped protuberance which is formed on the front sheet so as to protrude outside, can be reversed inside and includes an electrode provided therein;
a circuit member having a contact point with which the electrode are brought into contact when the protuberance is reversed;
a spacer sheet which is interposed between the front sheet and the circuit member, and includes a through hole formed therein for ensuring contact between the electrode and the contact point;
an adhesive sheet including on one side a circuit attaching surface for the circuit member and on the other side a bonding and fixing surface for an attaching member; and
an adhesive sheet-side accommodating portion, for accommodating a chip component mounted on a side of the circuit member where the contact is not disposed, formed in the adhesive sheet.
(4) The dome switch according to (3), wherein a recessed portion for the chip component is formed in the attaching member in correspondence with a position of said adhesive sheet-side accommodating portion.
(5) A dome switch comprising:
a front sheet;
a dome-shaped protuberance which is formed on the front sheet so as to protrude outside, can be reversed inside and includes an electrode provided therein;
a circuit member having a contact point with which the electrode are brought into contact when the protuberance is reversed;
a spacer sheet which is interposed between the front sheet and the circuit member, and includes a through hole formed therein for ensuring contact between the electrode and the contact point;
an adhesive sheet including on one side a circuit attaching surface for the circuit member and on the other side a bonding and fixing surface for an attaching member;
a spacer sheet-side accommodating portion, for accommodating a chip component mounted on a side of the circuit member where the contact is disposed, is formed in the spacer sheet; and
an adhesive sheet-side accommodating portion, for accommodating a chip component mounted on a side of the circuit member opposite to the side where the contact is disposed, is formed in the adhesive sheet.
(6) The dome switch according to (5), wherein an embossed portion for the chip component is formed in the surface sheet in correspondence with a position of the spacer sheet-side accommodating portion.
(7) The dome switch according to (5), wherein a recessed portion for the chip component is formed in the attaching member in correspondence with a position of the adhesive sheet-side accommodating portion.
(8) A dome switch comprising:
a front sheet;
a dome-shaped protuberance which is formed on the front sheet so as to protrude outside, can be reversed inside and includes an electrode provided therein;
a circuit member having a contact point with which the electrode are brought into contact when the protuberance is reversed;
a spacer sheet which is interposed between the front sheet and the circuit member, and includes a through hole formed therein for ensuring contact between the electrode and the contact point;
a light guiding portion, for accommodating and light guidance for a LED mounted on a side of the circuit member where the contact is disposed, formed in the spacer sheet; and
a light emitting portion, which is illuminated by light from the LED and through which the light can pass, formed in the surface sheet.
(9) The dome switch according to (8), wherein a light diffusing member for diffusing the light from the LED toward the light emitting portion is formed between the light guiding portion and the light emitting portion.
(10) The dome switch according to (8), further comprising:
an adhesive sheet having on one side a circuit attaching surface for the circuit member and on the other side a bonding and fixing surface for an attaching member; and
an external connection member provided on the circuit member so as to be used for electrical connection to an external circuit.
(11) The dome switch according to (10), wherein the external connection member includes edge connector terminals or a connector.
(12) The dome switch according to (11), wherein the external connection member includes a connection circuit portion led out from a circuit member body.
(13) The dome switch according to (10), wherein the adhesive sheet includes a release paper on the bonding and fixing surface.
(14) A dome switch comprising:
a front sheet;
a dome-shaped protuberance which is formed on the front sheet so as to protrude outside, can be reversed inside and includes an electrode provided therein;
a circuit member having a contact point with which the electrode are brought into contact when the protuberance is reversed;
a spacer sheet which is interposed between the front sheet and the circuit member, and includes a through hole formed therein for ensuring contact between the electrode and the contact point;
a light guiding portion, for accommodating and light guidance for a LED mounted on a side of the circuit member where the contact is disposed, formed in the spacer sheet;
a light collecting portion, for collecting the light guided by the light guiding portion, formed in the spacer sheet; and
a light emitting portion, which is illuminated by collected light from the light collecting portion and through which the light can pass, formed in the surface sheet.
(15) The dome switch according to (14), wherein a reflector is provided on obverse and reverse surfaces of the spacer sheet or on the inner surface of the surface sheet and the side of the circuit member where the contact is disposed.
(16) The dome switch according to (14), further comprising:
an adhesive sheet having on one side a circuit attaching surface for the circuit member and on the other side a bonding and fixing surface for an attaching member; and
an external connection member provided on the circuit member so as to be used for electrical connection to an external circuit.
(17) The dome switch according to (16), wherein the external connection member includes edge connector terminals or a connector.
(18) The dome switch according to (179, wherein the external connection member includes a connection circuit portion led out from a circuit member body.
(19) The dome switch according to (16), wherein the adhesive sheet includes a release paper on the bonding and fixing surface.
In accordance with the intention, in the assembly of the dome switch, the chip component mounted on the contact side of the circuit member is accommodated in the spacer sheet-side accommodating portion of the spacer sheet. By forming the spacer sheet-side accommodating portion in the spacer sheet, it becomes possible to mount the chip component on the contact side of the circuit member.
In accordance with the invention, in the assembly of the dome switch, the chip component mounted on a side of the circuit member opposite to its side where the contact is formed is accommodated in the adhesive sheet-side accommodating portion of the adhesive sheet. By forming the adhesive sheet-side accommodating portion in the adhesive sheet, it becomes possible to mount the chip component on the side of the circuit member opposite to the side where the contact is disposed.
In accordance with the invention, in the assembly of the dome switch, the chip component mounted on the contact side of the circuit member is accommodated in the spacer sheet-side accommodating portion of the spacer sheet. In addition, the chip component mounted on a side of the circuit member opposite to its side where the contact is formed is accommodated in the adhesive sheet-side accommodating portion of the adhesive sheet. By forming the spacer sheet-side accommodating portion in the spacer sheet, it becomes possible to mount the chip component on the contact side of the circuit member. Further, by forming the adhesive sheet-side accommodating portion in the adhesive sheet, it becomes possible to mount the chip component on the side of the circuit member opposite to the side where the contact is disposed.
In accordance with the invention, in a case where the height of the chip component mounted on the contact side of the circuit member is large, a tip portion of the chip portion is accommodated in the embossed portion of the surface sheet. By forming the embossed portion in the surface sheet, it becomes possible to mount the chip component with large height on the contact side of the circuit member.
In accordance with the invention, in a case where the height of the chip component mounted on the side of the circuit member opposite to the side where the contact is disposed is large, a tip portion of the chip portion is accommodated in the recessed portion of the attaching member. By forming the recessed portion in the attaching member, it becomes possible to mount the chip component with large height on the side of the circuit member opposite to the side where the contact is disposed.
In accordance with the invention, in the poly-dome switch, the LED is mounted on the circuit member. If the LED is made to emit light, the light from the LED is guided through the light guiding portion in the spacer sheet, and the light emitting portion of the surface sheet is illuminated. Further, the light emitting portion, as it were, emits light due to the light which passed through the light emitting portion. Meanwhile, in the assembly of the dome switch, the LED mounted on the circuit member is accommodated in the light guiding portion of the spacer sheet. By forming the light guiding portion in the spacer sheet, it becomes possible to mount the LED on the contact side of the circuit member.
In accordance with the invention, if the LED is made to emit light, the light emitting portion of the surface sheet is illuminate by the diffused light. Consequently, the light emitting portion is prevented from becoming partially bright.
In accordance with the invention, in the poly-dome switch, the LED is mounted on the circuit member. If the LED is made to emit light, the light from the LED is guided through the second light guiding portion and the light collecting portion in the spacer sheet, and the second light emitting portion of the surface sheet is illuminated. Further, the second light emitting portion, as it were, emits light due to the light which passed through the second light emitting portion. Meanwhile, in the assembly of the dome switch, the LED mounted on the circuit member is accommodated in the second light guiding portion of the spacer sheet. By forming the second light guiding portion in the spacer sheet, it becomes possible to mount the LED on the contact side of the circuit member.
In accordance with the invention, the light is efficiently guided between the second light guiding portion and the light collecting portion by the reflector.
In accordance with the invention, the adhesive sheet is further provided in the arrangement, and since the circuit member has the external connection member, the dome switch can be installed at a position which meets the user""s need. In addition, fixation is effected by merely attaching the bonding and fixing surface to the attaching member, so that the dome switch can be easily installed.
In accordance with the invention, electrical connection to an external circuit is effected by the edge connector terminals or the connector.
In accordance with the invention, electrical connection to an external circuit is made within the range of the length of the connection circuit portion led out from the circuit member body
In accordance with the invention, the bonding and fixing surface is protected up until the time of final use. In addition, the switch can be carried in a state in which the release paper is provided on the bonding and fixing surface.